Miyauchi Kenji, Yamamoto Yoshihiro, Kosaka Toshikazu, Hosoya Hiroshi
Department of Biological Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan.
Biochem Biophys Res Commun. 2006 Nov 24;350(3):543-8. doi: 10.1016/j.bbrc.2006.09.065. Epub 2006 Sep 22.
To elucidate whether phosphorylation of myosin II regulatory light chain (MRLC) is essential for myosin II recruitment to the furrow during cytokinesis, HeLa cells transfected with three types of GFP-tagged recombinant MRLCs, wild-type MRLC, non-phosphorylated form of MRLC, and phosphorylated form of MRLC, were examined. Living cell-imaging showed that both phosphorylated and non-phosphorylated form of MRLCs were recruited to the equator at the same time after anaphase onset, suggesting that phosphorylation of MRLC is not responsible for recruitment of myosin II to the equator. Moreover, the treatment with an inhibitor of myosin II activity, blebbistatin, induced no effect on recruitment of those three recombinant MRLCs. During cytokinesis, phosphorylated but not non-phosphorylated form of MRLC was retained in the equator. These results suggest that phosphorylation of MRLC is essential for retainment of myosin II in the furrow but not for initial recruitment of myosin II to the furrow in dividing HeLa cells.
为了阐明肌球蛋白II调节轻链（MRLC）的磷酸化对于细胞分裂期间肌球蛋白II募集到分裂沟是否至关重要，研究人员检测了转染了三种绿色荧光蛋白（GFP）标记的重组MRLC的HeLa细胞，即野生型MRLC、MRLC的非磷酸化形式和MRLC的磷酸化形式。活细胞成像显示，在后期开始后，磷酸化和非磷酸化形式的MRLC同时被募集到赤道，这表明MRLC的磷酸化与肌球蛋白II募集到赤道无关。此外，用肌球蛋白II活性抑制剂blebbistatin处理对这三种重组MRLC的募集没有影响。在细胞分裂期间，磷酸化而非非磷酸化形式的MRLC保留在赤道。这些结果表明，MRLC的磷酸化对于在分裂的HeLa细胞中肌球蛋白II保留在分裂沟中至关重要，但对于肌球蛋白II最初募集到分裂沟并非必需。
